Maybe this is a stupid question - I'm a total beginner at this stuff, but this makes me wary

Not stupid at all.

Judge Kendall has denied Chicago's MTD, which was based on the changed laws at the time the motion was filed. They have since changed even more.

What the Judge is saying is that from the Judicial standpoint, when a legislative body changes the law to moot a case, that the Courts will take at face value that the changes are made in good faith.

However, the plaintiffs have said that the changes are still in effect, a ban on gun ranges.

So the Judge is saying that it is on the plaintiffs to show that while these changes are designed to appear to mitigate the damages, they are still far short of the protections guaranteed by the 2A (as made obvious by the 7th Circuit). She is saying, "Show the court that these guys are just playing games and not acting in good faith."

They can do this in one of two ways: (1) challenge the constitutionality of these restrictions by filing an amended complaint as part of this case; or (2) file a new case attacking the same restrictions.

This is actually Judge Kendall holding out an olive branch to Alan Gura. The Circuit Court spanked her and she is now going to make nice.

I suspect and expect Ezell to file an amended complaint to show in specifics that Chicago is not willing to play nice.

Alan Gura can now charge Chicago for this litigation up to the point of the injunction, which will be issued shortly.

If he files a new case, then he is back to square one. By continuing this case with an amended complaint, he increases the likelihood of further wins and amount of money he can charge Chicago.

There is also the idea that should Mr. Gura prevail and show that Chicago is acting in bad faith, a Special Master can still be appointed by Judge Kendall. Chicago will have to pay for that, also.